Often the signs provided by a source of signs cannot be used straight after his strict production: it turns out a few times that there are demacioado fortresses, others, demaciado weak; other times, his graphic forms are not adapted for the device that must use them; other times it can happen that they do not produce in the opportune moment, etc. Of it it is deduced that it is necessary to prepare the signs. If a sign turns out to be too weak for his use, it is required that to amplify, that is to say, to increase his magnitude should be already in only one or in several successive stages, and it is what the amplifiers carry out.

Constitution of the Amplifiers

We already know, in general electronics, what a transformer is, and we might say that his mission is, in the fund, that of an amplifier since, as the tension of the secondary one does an ignition bobbin, for example, umenta greatly at the cost of reducing the intensity. There proves something like having a ticket of USD100 or 100 bielletes of USD1: the value is the same. Therefore there is no profit that is precisely what it distinguishes to the amplifier of the tranformador.

In this image we see a circuit where a transistor acts like amplifier, and which represents the form simplest and simple to carry out this basic circuit. Although circuits of this type can be done of a lot of forms, it is necessary to emphasize here the presence and disposition of the resistances R1, R2, R3, and R4, as well as of the condensers C1 and C2 that have for misiónpermitir the step of the alternating current across the cicuito amplifier and to avoid the step of the continuous one of one to another stage. In this respect it is necessary to bear in mind that the condenser cuts the step of the direct current but it allows to spend the alternating current and this is the case of the alternator, producer of the sign, in the image. As for the resistances, they determine the point of functioning of the transistor and, especially the R2, it acts also of protective element of the transistor opposite to the excess of temperature that is generated during the functioning of the semiconductor.
An amplifier of this type can turn out to be, for certain functions, with very little power an amplifier. Even if only one transistor can reach very well a factor of amplación of 100 (what means to do hundred vecesmás big the received sign) is necessary to bear in mind that one usually works with so weak signs, that this amplification can turn out to be completely insufficient. By it there are used amplifiers of two or more stages that increase to the square the value of the first amplification. This way, if we place an assembly as the showed one in the image joined to another fellow man we will be able to obtain 100 x 100 = 10.000 times the sign of exit top at the entry, and we might obtain still much more by means of coming to a third stage, etc.